Islamabad , Pakistan -LRB- CNN -RRB- -- Authorities in northern Pakistan were looking for 384 inmates who escaped from a prison early Sunday morning after hundreds of Taliban militants raided the facility .

The attack took place in the city of Bannu in northwest Pakistan , an area known for a heavy militant presence .

Four prison officials were wounded in the attack , which lasted more than two hours , said Iftikhar Khan , a senior police official in the city .

Of the 944 prisoners the facility held , 384 escaped , officials said .

Among them were 21 high-profile militants , said Iftikhar Hussain , the information minister of the Khyber Pakhtunkhwa Province , where Bannu is located .

The attackers apparently were aiming to free a senior Taliban commander , he said , but prison records were destroyed in the attack , and officials were still working to verify the names and crimes of those who escaped .

`` This is beyond terrorism . Such an attack challenges the writ of the state , '' Hussain said .

Two of the inmates who escaped had been awaiting execution .

One , Adnan Rashid , had been found guilty in the attempted murder of former President Pervez Musharraf in 2003 . The other , Safi Ullah , was convicted of several bombings in northern Pakistan in recent years , officials said .

Authorities were investigating how militants managed to enter the city , Hussain said .

`` A soul-searching investigation is underway to answer some big questions , '' he said . `` How were the militants allowed to block routes to the jail before the attack ? Why did n't the reinforcements arrive ? ''

The Pakistani Taliban claimed responsibility for the attack , according to its spokesman Ehsanullah Ehsan .

`` We will go where we need to go '' said Ehsan , vowing to continue attacks that would result in the release of other imprisoned Taliban fighters .

Journalist Wajahat S. Khan contributed to this report .

@highlight

NEW : Four prison officials are wounded in the two-hour attack , a police official says

@highlight

NEW : 21 of the 384 escapees were high-profile militants , an information minister says

@highlight

Attackers apparently aimed to free a senior Taliban commander , the information minister says

@highlight

The Pakistani Taliban claims responsibility and vows to continue attacks to release imprisoned militants